Original article: Hearthstone players are getting new challenges today. The first wing of single-player expansion Curse of Naxxramas will be released on PC, Mac and iPad.

The wing, called the Arachnid Quarter, is home to three bosses. Here's a brief description of each, from our complete boss guide published earlier in the month:

Crypt Lord Anub'Rekhan - Anub'Rekhan was once a leader of the nerubians, an intelligent and spider-like race that lived in secrecy for millenia before being conquered by the Lich King. The fallen nerubian lord was resurrected by the Lich King to guard the inner chambers of this wing.

Grand Widow Faerlina - Faerlina is a human cultist that helps raise the army of spiders produced in the Arachnid Quarter. The extensive time she spends with these spiders has made her proficient with poisons.

Maexxna - The source of the Lich King's spiders is Maexxna. This enormous spider will web and eat any intruders into her domain.

The Arachnid Quarter will be free to download for at least a month. After that, it'll cost you $6.99 or 700 gold to download. Blizzard will also let players buy multiple wings at once at a discount. The full price details can be found here.

Curse of Naxxramas' other four wings will be rolled out on a weekly basis. They'll be released in the following order: Plague Quarter, Military Quarter, Construct Quarter, and Frostwyrm Lair. Each wing contains a new set of bosses to defeat and cards to earn. After beating the wing once on Normal mode, you can replay it in Heroic for an added challenge.

Hearthstone's servers are currently down for extended maintenance. The Curse of Naxxramas content won't be playable right after maintenance is over, though.

"Just wanted to clarify that this maintenance is not for the Curse of Naxxramas Adventure," said community manager Aratil on the Battle.net forums. "We will be turning on Curse of Naxxramas for all regions at the same time some time after this maintenance is complete, but please do not expect Naxxramas to be available immediately following this maintenance."

The mention of an "all regions" release is interesting. Blizzard previously said that Europe wouldn't get it until the 23rd. I just assumed that they meant the North America and European launches of Naxxramas would be 24 hours apart. However, they might be planning to push out Naxxramas in the evening in North America today, which would be the early morning hours of Wednesday in Europe.

While you're waiting for Curse of Naxxramas to launch, check out the full list of cards in the expansion. Players will be able to add 30 cards to their collection, six of which are Legendary. They can also craft golden versions of these cards in time as well. These new cards will also be available for Arena mode once their corresponding wing goes live.